1. Field of the Invention
The present invention relates to a portable terminal, and in particular, to a sliding module for a portable terminal, to which a pair of housings of the portable terminal are slidably assembled.
2. Description of the Related Art
In general, the term “portable terminal” typically means an appliance for providing a mobile communication function to a user. Recently, portable terminals are provided with composite functions so that they can be used not only as mere mobile communication appliances but also as multimedia appliances for reproducing music files, moving image files, etc., or banking service appliances for use in micro payment and mobile banking.
Such a portable terminal is classified into a bar-type terminal, a flip-type terminal or a folder type terminal according to the appearance thereof. Recently, sliding-type terminals have appeared, wherein the sliding-type terminals occupy the majority of the portable terminal market together with folder-type terminals.
A bar-type terminal has a single housing which is provided with a keypad, an input/output apparatus such as a transmitter unit, a display device, and an output apparatus such as a receiver unit. Such a bar-type terminal is advantageous in that its construction is very simple because all the elements enabling the mobile communication function to be executed are provided in a single housing. However, it is necessary to secure a predetermined distance between the transmitter unit and the receiver unit for the purpose of voice communication. Therefore, there is a limit to such a bar-type terminal in terms of miniaturization.
A flip-type terminal is configured by rotatably mounting a flip cover on a bar-type terminal so as to close input devices such as a keypad in a communication standby mode, thereby preventing malfunction. However, there is also a limit to such a flip-type terminal in miniaturization due to the problem of securing a sufficient distance between the transmitter unit and the receiver unit thereof like the bar-type terminal.
A folder-type terminal includes a pair of housings which are foldably coupled to each other. Because input devices and output devices are arranged on the housings, respectively, such a folder-type terminal is advantageous in miniaturization and easy to secure a sufficient distance between the transmitter unit and the receiver unit thereof. As a result, folder-type terminals have occupied most of the portable terminal market for a long time.
A sliding-type portable terminal includes a pair of housings slidably coupled to each other. Because input devices and output devices are arranged on the housings, respectively, and a keypad, which is one of the input devices, is opened or closed as the housings are slid, such a sliding-type portable terminal has several advantages in that the input devices such as the keypad can be protected better, and the portable terminal is easy to use and advantageous in miniaturization. For this reason, sliding-type terminals have gradually gained the folder-type terminals' market share and the market share of sliding-type terminals rather has exceeded that of the folder-type terminals.
As multimedia service and real time broadcasting service using portable terminals have been revitalized, satellite digital multimedia broadcasting and terrestrial digital multimedia broadcasting have been commercialized.
Ordinary mobile communication services, such as voice communication, short message service, mobile internet access, etc., use frequencies in the 800 MHz frequency band or in the 1.8 GHz frequency band. However, satellite digital multimedia broadcasting uses frequencies in the 2.6 GHz frequency band, and terrestrial digital broadcasting uses frequencies in the 174 to 216 MHz frequency band. As a result, in order to receive digital multimedia broadcasting, it is necessary to provide a separate antenna apart from an antenna for use in ordinary mobile communication.
In a sliding-type terminal, however, metallic components configuring the sliding module thereof form a main cause of hindering the action of such an antenna. In addition, an antenna for receiving broadcasting of a low frequency band such as terrestrial digital multimedia broadcasting is not only greatly affected by structures in the neighborhood thereof, but also subjected to abrupt deterioration in performance for receiving terrestrial digital multimedia broadcasting when an electric field or the like is induced between the components of the sliding module due to high frequency noise occurring from the terminal itself, by which the design of such an antenna is restricted.